This invention is generally directed to an improved interface for use in connection with a telecommunication system. A telecommunication system often includes a telephone switching system and an adjunct processor such as a voice messaging system (VMS).
The telephone switching system processes messages from multiple telephones and their users. These messages are often further processed and stored in the VMS.
Messages in the telecommunication system are comprised of a voice and a data message component. The voice component relates to the voice message which has been recorded and the data component identifies information, such as, where the call originated, the destination of the call, and the time of the call. The data component of the message can also include, for example, signaling to turn off or on a light on the telephone to indicate whether messages directed to the user are waiting for delivery in the VMS.
A problem which is often encountered in a telecommunication system is that the telephone switching system utilizes a different protocol than the adjunct processor. A protocol is a set of rules governing the format of data which is exchanged between microprocessors. Two types of protocols, for example, are Application Processor Interface (API) and Simplified Message Service Interface (SMSI). In order for data messages to be forwarded from the telephone switch to the adjunct processor, the microprocessor within the adjunct processor must recognize the protocol of the data messages from the telephone switch. Likewise, in order for data messages to be forwarded from the adjunct processor to the telephone switch, the microprocessor within the telephone switch must recognize the protocol of the data messages from the adjunct processor. Often however, telecommunication switches and adjunct processors do not utilize the same protocol. For example, many switches operate using API protocol and many VMS operate using SMSI protocol. In order for the VMS and the telecommunication switch to operate together an interface (or protocol converter) is needed to convert the API protocol messages delivered from the switch to SMSI protocol. Once the data is formatted in SMSI protocol, the data can be utilized by the VMS. Similarly, the data delivered from the VMS is converted from SMSI protocol to API protocol so that it may be utilized by the switch.
In the past, interfaces have been used to accomplish the translation of data messages between telephone switches and VMS. A number of problems, however, have been encountered when these interfaces are implemented. First, the number of messages which can be transmitted between the switch and the VMS is limited by the capacity of the interface. Another problem is the failure of the transmission link provided by the interface. Because all messages to be processed by the VMS must be transmitted through the interface's single link, if the link fails, no messages can be delivered to the VMS. Moreover, when links fail it is often difficult to determine the cause of the failure.
Previously the problems of link failure have been solved by connecting an additional interface between the telephone switch and the VMS. The use of a second interface, however, doubles the cost of the system and the space required for housing the system. Additionally, although additional capacity is provided by the second interface, this additional capacity is often unnecessary. In many situations, the capacity provided by a single interface is sufficient to meet the demands of the system. The problem rather lies in failure of the link provided by the interface and the inability of the interface to process and translate data messages upon failure of the link.
A telephone system 100 which provides connection between a number of switches 102 and a VMS 104 is shown in FIG. 5. Two connections are provided between each switch 102 and the VMS 104 to carry the communication signals between the switches 102 and the VMS 104. A first connection carries the voice portion 106 of the communication signal and the second connection carries a data portion 108 of the signal. The voice portion 106 of the signal is carried directly over the first connection from the switch 102 to the VMS 104 and vice versa. The data portion 108 of the signal typically includes a message waiting indicator (MWI) portion, for example, which provides an instruction from the VMS 104 to turn on/off a light on a telephone 110 in communication with the switch 102 and provides an indication as to whether the user has messages waiting at the VMS 104. As discussed above, because the protocol of the switch 102 is often different than the protocol used by the VMS 104, a translator or interface 112, translates the data from the protocol used by the VMS 104 to the protocol used by the switch 102 and vice versa to provide communication between the VMS 104 and the switch 102.
Modems 114 are used to transmit the data signals 108 between the interface 112 and the VMS 104. Once the connection is obtained with a modem 114, the data is streamed from point-to-point along the circuit. Thus, several connections are provided in order to carry the data signals 108 between the switch 102 and the VMS 104. These connections are subject to breakage and failure and the reasons for failure may be difficult to determine. Often it is necessary for an individual to inspect the various connections to determine the cause of failure. Any number of occurrences can cause failure of the numerous connections. For example, a cable may be broken during a digging operation or a modem may fail. Any of these failures prevent the data from being transmitted along the points and therefore between the switch 102 and the VMS 104.
The present invention provides an improved interface which overcomes the problems presented in the prior art and which provides additional advantages over the prior art, such advantages will become clear upon a reading of the attached specification in combination with a study of the drawings.